Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 36: TR: Poster Session
TT 36.28: Poster
Donnerstag, 25. März 2010, 14:00–18:00, Poster A
Dual-path measurements of the noise properties of Josephson parametric amplifiers — •Alexander Baust1, Edwin P. Menzel1, Matteo Mariantoni1, Frank Deppe1, Miguel Angel Araque Caballero1, Elisabeth Hoffmann1, Thomas Niemczyk1, Achim Marx1, Rudolf Gross1, Enrique Solano2, Kunihiro Inomata3, Tsuyoshi Yamamoto3,4, and Yasunobu Nakamura3,4 — 1Walther-Meissner-Institut and TU München, Garching, Germany — 2Universidad del Pais Vasco and Ikerbasque Foundation, Bilbao, Spain — 3RIKEN, Wako, Japan — 4NEC Corporation, Tsukuba, Japan
Phase sensitive amplifiers, e.g. Josephson parametric amplifiers (JPA), in principle allow for the amplification of one signal quadrature without adding noise. In practice however, internal losses introduce noise. In experiments, the JPA output signal usually is further amplified by HEMT amplifiers, which obscure the noise properties of the JPA by their much larger noise. We show that splitting the signal and utilizing two amplification chains allows one to eliminate the noise contribution of the HEMT amplifiers. In this way, the first two signal moments can be analyzed by correlation measurements. We study two possible applications of our dual-path method. First, we investigate the noise properties of a superconducting JPA. Second, we address the measurement of squeezed states generated by the latter and discuss to what extent squeezing can be observed in our samples.
We acknowledge support from SFB631, NIM, UPV/EHU Grant GIU07/40 and European project EuroSQIP.